Constructing a multiple level building commonly requires the use of OSHA mandated safety fences or guardrails installed temporarily along the edges of elevated work surfaces such as upper floors, decks, slabs, platforms, roofs and stairways. Such elevated building features are referred to collectively herein as “decks” and that term should be understood to include any generally horizontal or inclined building structure that supports construction workers and has opposing upper and lower surfaces. Conventional safety fences and guardrails employed on construction sites are intended to provide persons working on the building with at least some measure of protection against falls, at least until a surrounding wall or other restraint is completed. Temporary safety fences typically utilize a series of vertical posts or stanchions, and horizontal rails that interconnect the stanchions. Such fences may also include elongate toe boards that help prevent debris and/or work equipment from falling off of the elevated surface and presenting a serious safety hazard.
A variety of supportive devices have been developed for holding the upright posts or stanchions of a construction safety fence. As required by OSHA, these devices must be mechanically attached to the supporting deck structure. Although an assortment of clamps and brackets are available for this purpose, most safety fence mounting systems feature a base plate that is screwed or bolted by a tap-con or similar fastener to the underlying deck (which is itself typically composed of concrete). In an alternative technique, expansion anchors are drilled into the deck and the stanchion supporting device is bolted to the anchor itself.
To provide an acceptable degree of safety, the guardrail or safety fence must be fastened as securely as possible to the deck structure. The strength, safety and effectiveness of the fence is severely compromised if the fastening attachments are of poor quality or are not sufficiently strong for a particular application. By the same token, poor workmanship or installation equipment can reduce the extraction (removal) strength of the safety fence considerably. In any event, the effective strength of the fence is limited by the fracture strength of the tap-con, screw, bolt or other fastener. In many building construction applications, this has proven to be inadequate. Typically, the fastener is embedded only a short distance into the deck. In other cases, faulty equipment or poor workmanship causes mounting holes to be improperly sized. Either circumstance can cause the fastener to accidentally separate from the deck and thereby significantly weaken the safety fence.
An additional shortcoming of conventional stanchion or post mounting devices is that these devices do not provide a secure and conveniently accessible anchoring point for holding a safety strap and attached construction worker so that the worker is protected against potentially deadly falls. Conventional construction anchoring points are rarely installed near the perimeter of an elevated deck. Rather, they tend to be located near the center of the deck, slab or floor. As a result, safety lines attached to the anchoring point can pose a serious tripping hazard for workers. In addition, because safety lines cannot be practically or conveniently installed around the perimeter of an elevated deck, such lines cannot be easily extended and used effectively between different floors of a multiple level building. The versatility of known safety fence support systems is therefore quite limited.